1. Field of the Invention
The present invention relates data transmission between an operating unit and a controller of an image forming apparatus.
2. Description of the Related Art
In a conventional image forming apparatus, data is bidirectionally transferred between an operating unit and a controller with a synchronous serial communication method. To realize the bidirectional data transfer, the operating unit and the controller are connected to each other with four signal lines including two data lines and two clock lines. Furthermore, Japanese Patent Application Laid-open No. 2004-96496 teaches to use a peripheral component interconnect (PCI) bus for performing data transfer between an engine and a controller.
However, the image forming apparatus employing the synchronous serial communication method has problems in a transfer rate and a susceptibility to a noise when the transfer rate is about 1 Mbps. Particularly, with the developments of various functions with image data, such as functions for displaying a preview image and a thumbnail image, there has been a tremendous increase in the amount of data that needs to be transferred between the operating unit and the controller. Therefore, there is a need to increase the data transfer speed between the operating unit and the controller of the image forming apparatus.